Mast



July 27, 1965 R. L. JOHNSON ETAL 3,196,991

MAST

Filed May 4, 1962 5 Sheets-Sheet l Will 60 m 43 El. 55 1 i 1 INVENTORS,

RICHARD L. JOHNSON HENRY L. SCHIFF, deceased BY ZQON H.scmyminisfla'rrix ATTORNEY.

y 7, 1965 R. JOHNSON ETAL 3,196,991

' MAST Filed May 4. 1962 3 Sheets-Sheet 2 FIG? INVENTORS, RICHARD LJOHNSON HENRY L. SGHIFF, deceased BY RION RigyFF, dminisfmhx ATTORNEY y7, 1965 V R. L. JOHNSON ETAL 3,196,991

MAST

Filed May 4, 1962 5 Sheets-Sheet 3 U U INVENTORS,

RICHARD L. JOHNSON HENRY L. SCHIFF, deceased yon H. scW, qdzinishmrixATTORNEY.

United States Patent 3,196,991 MAST Richard 1.. Johnson, Red Bank, N.J.,and Henry L. Schifi, deceased, late of Wall Township, Monmouth County,Nl, by Marion H. Schitt, administratrix, Freehold, N "1., assigncrs tothe United States of America as represented by the Secretary of the ArmyFiled May 4, 1962, Ser. No. 192,611 1 Claim. (Cl. 189-26) (Granted underTitle 35, US. Code (1952), see. 266) The invention described herein maybe manufactured and used by or for the Government for governmentalpurposes, without the payment of any royalty thereon.

The present invention relates to extensible and retractable maststructures particularly adapted for use in supporting radio, televisionor radar antenna or similar devices.

An object of the invention is the provision of a tower or mast which maybe readily transported from location to location, and which may bequickly and easily set up for use.

A further object of the invention is the provision of a mast which is ofuse to the mobile branches of military forces which require quick andefiicient installations and he removal of equipment with dispatch whenthe occasions arise.

A further object of the invention is the provision of an extensible andretractable mast which may be readily collapsed and may be compactlycrated for shipment to other locations.

Another object of the invention is to provide a mast structure of thistype with telescoping members which lock themselves automatically whenbrought into their extended position and which cannot be unlocked by thestress or strain produced by the forces acting upon the mast and/ or theantenna upon the mast.

It is a further object of the invention to provide a mast structure oftelescoping rods which unlock themselves automatically by a combinationof simple devices without regard to the strain to which the mast issubjected by gravity or by prevailing atmospheric conditions.

Another object of the invention is to provide a support mast having newand improved valve means for raising and lowering the same.

Other objects and features of the invention as well as the combinationand construction of parts will be apparent from the followingdescription and from the accompanyin g drawings in which:

FIGURE 1 is a side elevational view of a completely erected mastassembly illustrative of the invention;

FIGURE 2 is a side elevational view of the mast in its collapsedarrangement;

FIGURE 3 is an elevational view of the uppermost section of the mast;

FIGURE 4 is a cross sectional view of the uppermost section taken on theline 44 of FIGURE 3;

FIGURE 5 is a sectional View of the locking collar, with a partial Viewof a guy support ring, as seen when in locked position;

FIGURE 6 is a view of the locking collar of FIGURE 5 shown when open orunlocked;

FIGURE 7 is an elevational view, and partly cut away showing a mastsection and its locking collar with its associated air valve;

FIGURE 8 is an enlarged diagrammatic view showing the operativepositions of the locking bolt of the locking collar;

FIGURE 9 is a top plan view of an air valve forming part of the maststructure;

FIGURE 10 is a sectional view of the air valve taken on the line 19-113of FIGURE 9.

3,196,991 Patented July 27, 1965 For an over-all picture of the mastreference is made to FIGURES 1 and 2 wherein the mast of the presentinvention is shown in extended and collapsed positions respectively. InFIGURE 1, the mast generally designated as 11, is made of a plurality ofdiscrete mast sections 13, 15, 17, 19, 21, 23, 25, and 27 Each of saidsections are of substantially the same length. However each section isof a smaller width than the section preceding it, so that the sectionscan be telescopically stacked as can be seen in FIGURE 2. The extensiblemast 11 is supported on a base 29 by having the first mast section 13adequately secured thereto. The section 13 also includes a port 31 whichserves as an inlet for a pressure medium, such as air or a liquid, forraising the mast sections as hereinafter described. Also afiixed to themast section 13 is a reel 33 provided with a handle for afiording manualoperation of the reel. While a hand operated reel has been shown, it isobvious that a motorized reel can be provided. The reel 33 serves as ahousing for a cable 35, one end of said cable being affixed to the shaftof the reel, while the other end of the cable is anchored into andwithin the mast section 27. The cable 35 includes a weight 37, in theform of a plumb beveled at each of its ends. The weight or plumb 37 isutilized in the operation and functioning of the locking collars when itis desired to lower the mast from its fully extended position ashereinafter more fully described.

Each of the mast sections 1325, and with the exception of section 27, isprovided with a locking collar, generally designated as 39, adjacent tothe top of each of said sections. Each of the collars are of identicalconstruction, except for a reduction in size of the successive collarson the respective successive smaller width mast sections as is apparentfrom the inspection of FIGURE 1 which shows the successive smallercollar on the mast sections. One such typical collar, is shown inFIGURES 5 and 6 in respective locked and unlocked positions, and furthershown, partially cut away, in FIGURE 7. In the views, as seen in FIGURES5, 6, and 7, a portion of the fully extended mast structure between mastsections 17 and 19, and its associated locking collar 39, is shown. Inthis regard, FIGURE 7 shows the upper portion of mast section 17 whichsurrounds and is in locked telescopic relation with its next adjacentmast section 19. The locking collar 39 of the mast ection 17 is securedimmediately adjacent to the upper rim of the section 17 and, as shown inFIGURE 7 serves to lock the next upper section 19. Such lockedengagement of the sections 17 and 19 is eiiected by the engagement of alocking bolt 61, and a ring 41 that is aiiixed to the outer surface ofthe section 19. The ring 41 is provided with a slot 43 within which maybe accommodated the locking bolt 61 referred to above, for securelylocking the .mast section 19 in its fully extended position, as shown inFIGURE 7. It is to be noted that the ring 41 is spaced a short distancefrom the bottom of the mast section 19 so as to aiiord a-more stable andrigid confinement of the section 1% within section 17 when in lockedengagement.

The arrangement of one of the locking collars 39 is shown in FIGURES 5and 6. In the specific example shown in said figures of the drawing itis that collar between the mast sections 17 and 19. The collar assemblyincludes a one piece housing 45 secured adjacent the top rim of a mastsection 17. The housing is suitably secured to the section by bolts 47or any other means. The housing includes a fitting 49 through which alubricant, such as grease or oil can be forced into and within thehousing 45. The housing also includes a peripheral slot 51 within whichare seated a pair of identical arcuate shaped locking arms 53, 55 which,in locked position as in FIGURE 5, substantially engirdle the mastsection 19. The arms 53, 55 are pivotally mounted on pins 57, 59

. 3 which are confined in the housing 45. Forming part of the lockingcollar are springs 60 located between the secured ends of the arms 53,55 and the housing which function to normally urge the free ends of thearms toward each other. When so urged toward each other, the discretefree ends of the separate arms do not abut, but are spaced from eachother to form a gap 62 which is in register with an opening 64 in thehousing. Each of the locking arms has aflixed therein the transversefloating locking bolt 61. The bolt61 is supported by a pin 63 that isconfined within the housing 45. The pin 63 is in turn slidably engagablein a slot 65 in the locking arm 53 to permit said locking arm to bemoved away from a mast section when the locking bolt is to be disengagedfrom its locked position as hereinafter described. 7 1

To elevate the mast structure described herein, use is made of a fluidpressure medium such as air, water or other liquid. In the specificembodiment shown use is made of air as the pressure medium, and in thisregard we have devised a new and novel air valve to regulate the flow ofair into the mast structure. Such air valve is shown in FIGURES 9 andand generally designated as 67. Each of the mast sections, except forthe first secured section 13, has an identical air valve bolted, orotherwise secured, within the bottom end of the mast section as can beseen in FIGURE 7. The air valve 67 includes a cylindrical body portion69 having a peripheral flange 71 about its top edge. gasket 73 to effectan airtight seal of the valve 67 within the mast section. The bodyportion 69 includes an inverted T shaped central cavity .75 whichincludes an enlarged base cavity 75A. The housing 69 further includes aplurality of tubular passageways one of which is shown, in crosssection, as 77 and having areduced portion 77A. within each of saidpassageways are confined a ball 79, of metal or the like, having adiameter larger than the reduced portion 77A, but of smaller diameterthan the main portion 77 of the passageway. By such arrangement the ballis free to ride in the portion 77, but constrained from escape from thehousing as is evident from an inspection of FIGURE 10 of the drawing.The ball 79 is normally urged downward, as viewed in FIGURE 10, by' aspring 81. One end of the springSl abuts against the ball 79, while theother end engages the underside of a plate 83 in the upper part of thebody portion 69. The plate is secured to the housing by four bolts, oneof which is shown at 85. Theplate 83 includes a central opening 87 inregister with the cavity 75 and a plurality of openings 89 each inregister with the passageways 77, however of a diameter smaller than thepassageway 77. Also'shown are a series of bolts 91 in suitable openingswhich are. used to secure the air valve 67 within a mast section. Withinthe body 69 is a-confined cavity 93 having a reduced portion 93A whichis in open communication with the cavity portion 75A of the entralcavity 75. Within the cavity 93 is a ball 95 which is normally urgedagainst the reduced portion 93A of the cavity 93 by a lightly tensionedspring 97, one end of which abuts against the ball 95 while its otherend engages the underside of the plate 83. Extending through the sidewall of the body portion69 and into the cavity 93 is a passageway 99which allows for an egress of air during the lowering of the maststructure as hereinafter described.

In FIGURE 4 there is shown a sectional view of the topmost section 27 ofthe mast and the arrangement for securing the cable 35 and its plumbWeight 37. The mast section 27 is shown in extended position andsecurely held by the locking collar 39 of the preceding mast section 25.As earlier described one end of the cable is secured .to the reel 33,and the other end of the cable is secured adjacent to the upper end of amovable cylindrical block 191 that is adapted to ride within the mastsection. Secured to the lower end of the block 1191 is one end ofBeneath the flange is seated a sealing a spring 193. The other end ofthe spring 163 is secured to a fixed anchor 1635 within the mast section27.

The steps in the raising of the mast structure from its collapsedposition, as shown in FIGURE 2, is as follows. An air line is afiixed tofitting .31 to introduce an air pressure into the mast structure. As theair pressure increases, the first mast section 15 will be raised andcarry along with it all the remaining sections in unison. At this timesection 15 will be locked in section 13 as hereinafter described. As theair pressure is further increased, air will overcome the resistance ofthe several springs 51 inthe passageway 77 thereby forcing the ball 79from its locked position and permit air to rush through the sixpassageways 77. In this manner air pressure is sufficientlybuiltup toraisethe next mast section and lock said section. The remaining sectionsof the mast are then separately raised in the same manner.

The manner in which anyone of the locking collars 39 function is asfollows, typified by the collar on mast section 13.' As the section 15is being separately elevated, carrying along with it all the other mastsections in unison, the cable 35 will begin to unwind from the reel 33and be carried upward as the topmost section, to which the other end ofthe cable is secured, is being raised. As the mast sections are beingraised, the plumb weight 37 will readily engage and begin to passthrough the gap 62 between the spring loaded arms 53, 55 and urge saidarms apart as shown in FIGURE 6. Momentarily thereafter the locking bolt61 will engage the ring 41 of the section 15. Such engagement willfurther urge the arms apart. As the section 15is still being raised,,the plumb weight 37 will have already passed through the gap 62 and thebolt will be urged into engagement with the slot portion 43 or the ring41 to thereby lock and secure the section 15 within section 13. Toassist in the alignment of the mast sections, each of the sections isprovided with oppositely disposed keys 196 that engage keyways 107 inthe housing 45. It will be apparent that each of the mast sections willbe locked in similar manner. After the mast is fully extended as inFIGURE 1, the air line can be removed from the fitting 31. Any loss ofair pressure from the mast structure will be of no import, since noreliance is made upon internal pressure to support the mast structure inits elevated position. The mast structure is held rigid by the system oflocking collars 39 and guy supports extending from a guy collar 1179alfixed to the housing 45. As seen in FIGURE 2, several such guy collarsare provided to provide any desired number of guy lines that extend tothe ground.

When the mast is fully extended the plumb weight 37 will be positionedabove the locking collar of mast section 25. When it is desired to lowerthe mast to its collapsed position, the reel 33 is rotated to draw thecable 35 on to the reel. As the cable descends the plumb weight willtravel through the gap 62 between the arms 53, 55 thereby urging saidarms apart. Such movement of the armswill release the locking bolt 61from engagement with the slot 43 thereby allowing the section 27 tofall.

As the mast section 27 is falling, any normal air pres-' sure within thesection will be dissipated through the air valve by the air entering thecavity of the air valve then into the portion 75A. The air then flows,or is forced, through the reduced portion 93A of passageway 93. Suchmovement of air is suflicient to force the ball upward to overcome thepressure of spring 97. The

air is then free to escape through opening 99. This same action isrepeated as each of the mast sections is unlocked from its securedposition. By such means a gradual and controlled descent of the maststructure can ends adjacent said base section, each valve being operableby a pressure medium used for raising the discrete successive mastsections to their fully extended position, a

locking collar on each of said mast sections, said locking collarincluding a pair of opposed spring loaded arms pivotally secured to eachsection at the end thereof opposite the first mentioned end, said armsengirdling and securing the next mast section of smaller diameter assaid mast structure is being raised, means for unlocking said collars torelease the secured mast section therein, said means comprising a cablespaced from the mast sections and having one end secured within a reelon the base section and its other end secured within the topmost mastsection, a wei ht fixed to said cable intermediate its ends, said weightbeing adapted to engage contiguous ends of said arms to open same intounlocking relationship With said sections as said mast sections andWeight are being raised and lowered.

References Cited by the Examiner UNITED STATES PATENTS 15 FRANK L.ABBGTT, Primary Examiner.

HENRY C. SUTHERLAND, JACOB L. NACKENOFF,

Examiners.

